RESUMO
AIM: To analyze the neurotoxic potential of synthesized magnetite nanoparticles coated by dextran, hydroxyethyl starch, oxidized hydroxyethyl starch, and chitosan, and magnetic nanoparticles combined with ferritin as a native protein. METHODS: The size of nanoparticles was analyzed using photon correlation spectroscopy, their effects on the conductance of planar lipid membrane by planar lipid bilayer technique, membrane potential and acidification of synaptic vesicles by spectrofluorimetry, and glutamate uptake and ambient level of glutamate in isolated rat brain nerve terminals (synaptosomes) by radiolabeled assay. RESULTS: Uncoated synthesized magnetite nanoparticles and nanoparticles coated by different polysaccharides had no significant effect on synaptic vesicle acidification, the initial velocity of L-[(14)C]glutamate uptake, ambient level of L-[(14)C]glutamate and the potential of the plasma membrane of synaptosomes, and conductance of planar lipid membrane. Native ferritin-based magnetic nanoparticles had no effect on the membrane potential but significantly reduced L-[(14)C]glutamate transport in synaptosomes and acidification of synaptic vesicles. CONCLUSIONS: Our study indicates that synthesized magnetite nanoparticles in contrast to ferritin have no effects on the functional state and glutamate transport of nerve terminals, and so ferritin cannot be used as a prototype, analogue, or model of polysaccharide-coated magnetic nanoparticle in toxicity risk assessment and manipulation of nerve terminals by external magnetic fields. Still, the ability of ferritin to change the functional state of nerve terminals in combination with its magnetic properties suggests its biotechnological potential.